[Spatial distribution and evaluation of nitrogen, phosphorus and organic matter in surface sediments from western lakeside belt of Lake Taihu].

The surface sediments in western lakeside belt of Taihu Lake were collected. The spatial distribution of nutrients and pollution evaluation were studied. The results showed that concentration of the nitrogen, phosphorus and organic matter in the surface sediments had an increasing tendency from inshore to the far shore.

[Calculation of environmental dredging depth of heavy sediments in Zhushan Bay of Taihu Lake metal polluted].

Horizontal distribution of heavy metals in surface sediments of Zhushan Bay was investigated, and core sediment samples were collected in the representative area. Core sediments were divided into oxide layer (A), polluted layer (B), upper polluted transition layer(C1), lower polluted transition layer(C2) and normal mud layer(D) from top to bottom. The change of total contents of Cr, Ni, Cu, Zn, As, Cd, Hg, Pb and contents of biological available Cr, Ni, Cu, Zn, As, Cd, Pb with depths were analyzed.

[Effects of sediment on the growth of Microcystis and Anabaena in Yanghe reservoir].

Batch culture experiments were used to study the effect of leachate from sediment of Yanghe reservoir on the growth of Microcystis and Anabaena isolated from Yanghe reservoir. The results showed that the growth of Microcystis was significantly inhibited when the addition of anaerobic leachate from sediment in M11 culture medium was high (> or = 20% V/V). The maximum biomass of Microcystis was lower than that grown in pure M11 culture medium.

[Classification and pollution characteristic analysis for inflow rivers of Chaohu Lake].

Based on main pollution sources and characteristics of inflow rivers of Chaohu Lake, the inflow rivers are clustered and the pollution levels are classified by statistical methods. In addition, the correlation between algal biomass and the river nutrients input loads is derived according to the inflow river water quality monitoring parameters and the Chl-a concentrations in lake areas. Results show that the inflow rivers are classified into three groups.

[Relationship between the DO and the environmental factors of the water body in Lake Erhai].

The contents of DO and nitrogen (N), phosphorus (P), chlorophyll a in water from Lake Erhai were analysed by combining the nitrogen and phosphorus forms in sediment. The results indicated that the DO contents of the water from Lake Erhai varied from 6.61 to 7.

[Influence of disturbance intensity on nitrogen, phosphorus and permanganate index release of Potamogeton crispus during soaking in water].

Influence of various disturbance intensities on nitrogen, phosphorus and permanganate index (PI) release of Potamogeton crispus were investigated during the plant soaking in water, and the plant materials were collected in an urban lake of Beijing. Results showed that more rapid release of TP and PI from Potamogeton crispus were caused by disturbance, NH4(+) -N and TN in water were significantly increased (ANOVA, p < 0.05) under the condition of high disturbance (120 r/min) for 240 h.

[Characteristic analysis of the adsorption/desorption of nitrogen and phosphorus in the sediments of Taihu Lake].

The adsorption isotherms curves of 90 simples were studied in Taihu Lake through the experiment of adsorption/desorption. And the relation between the equilibrium concentrations, NAP, adsorption efficiency and corresponding parameter in interstitial water and sediment has been analyzed, in order to analyze the "source" and "collection" of Taihu. The results showed that the isotherms curves of nitrogen and phosphorus in the sediment had significant correlations in the range of the concentrations of experiment.

[Effect of different type sediments on transformation of phosphorus forms and growth of Myriophyllum spicatum].

The changes of the different phosphorus (P) forms in sediments, overlying water and the diversity of dry weight and root forms of Myriophyllum spicatum were studied using different type sediments under simulating condition. The characteristic of transformation of P forms and growth of submerged plant Myriophyllum spicatum were illustrated. The results indicated that the P release was promoted by adding the silver sand in sediment, and their P concentrations in the overlying water were increased.

[Heavy metals pollution and its stability assessment of sediments in flowing rivers around lake Taihu].

16 main inflow and outflow rivers around Lake Taihu were chosen as the research object, and the concentrations and distribution of four heavy metals (Pb, Cd, Cu and Zn) in the surface sediments of these river estuaries were detected. The pollution extent and stability were analyzed by using three-step sequential extraction method (BCR method). Aim of this study is to control heavy metal pollution of Lake Taihu and provide the basic information.

[Seasonal variation characteristics of algae biomass in Chaohu Lake].

The biomass and distribution of algae community in Chaohu Lake were investigated in 2008. At the same time, the seasonal variations of algae translocation between the sediment and overlying water were also quantitative studied by self-made "algae up/down trap". Chaohu Lake was dominated by Cyanobacteria all the year, and dominant Cyanobacteria species changed in different seasons.

[Seasonal occurrence characteristics of different forms of nitrogen in the sediments of Chaohu Lake].

Seasonal characteristics of the free nitrogen (FN), the exchangeable nitrogen (EN), the acid hydrolysable nitrogen (HN) and the residual nitrogen (RN) in the surface sediment of Chaohu Lake were analyzed by sequential extraction method. The correlations among the nitrogen fractions with the total nitrogen (TN) and the mineralizable nitrogen (MN) were discussed considering the seasonal variations of the TN and MN. The results show that the concentrations of FN, EN and TN are lower in summer and higher in autumn and winter, NH4(+)-N is the main fraction of FN and EN.

[Diurnal variations in purifying-tanks when use Pontederia cordata treating the Malodorous River water].

Aquatic plants (Ponsederie cordaza) were waked in two purifying-tanks to investigate the effects of illumination intensity and aeration on diurnal variations of Chla, SP, POD of Ponsederia cordaza and pH, DO, COD, NH4+ -N, TP of water from purifying-tanks when treating the malodorous river water at seven different times, another blank purifying-tank was set as a control. Comparative studies and correlation analysis of these different indicators were carried out to improve the plants working efficiency and provide scientific basis for optimal operation of plant purifying-tanks. Results showed that all indicators affected by changes of light, TP shows best correlation coefficient Cr = 0.

[Physiological responses of Myriophyllum spicatum to ammonium nitrogen].

With the sediment applied with 0, 0.24%, and 0.48% NH4Cl (treatments CK, SN1, and SN2) as the substrate, a greenhouse experiment was conducted to study the physiological responses of Myriophyllum spicatum to ammonium nitrogen.

[Effect of inactivation agents on the phosphorus release from sediment of Lake Dianchi at different temperature].

The influence of temperature on P release from sediment of Lake Dianchi was discussed. Two kinds of inactivation agent schemes (Al2SO4.18H2O and PAC-Polymeric Aluminum Chloride) were used.

[Buoyancy regulation and vertical distribution of Planktothrix mougeotii in the simulator experiments].

The dominance of gas-vacuolated cyanobacteria is often attributed to their buoyancy and buoyancy in response to environmental conditions. Lake simulator experiments (4 m high and 1 m diameter) and pyrex bottle experiments (10 L) were applied to investigate the buoyancy regulation and vertical distribution of Planktothrix mougeotii in eutrophic lakes at 28 degrees C. During light phase, the filaments stratify in the 2-3 m after 8 h light exposure and the biomass at the layer attach maximum after 12 h light exposure.

[Effects of EDTA and iron on growth and competition of Microcystis aeruginosa and Scenedesmus quadricauda].

Not only population density of phytoplankton but also its community structure were influenced by iron limitation. The growth and competition of a cyanobacterium Microcystis aeruginosa and a green alga Scenedesmus quadricauda at different iron and EDTA concentrations were investigated using batch cultures. The results showed that the growth of M.

[Critical collapse pressure of gas vesicles in six strains of cyanobacteria].

Two methods including filtration (vacuity is 0.02 MPa) and centrifugation ( < 500 r/min) were applied to concentrate algal biomass, and capillary compression tube and the concentrated algae suspensions, critical pressure distribution of gas vesicles in six cyanobacteria were also investigated. The results showed that unicellular Microcystis aeruginosa cells couldn't be concentrated effectively by filtration or centrifugation, but colony of Microcystis wesenbergii and Microcystis flosaquae, and filament of Planktothrix mougeotii could be concentrated by centrifugation and filtration respectively.

[Effects of silicate on the community structure of phytoplankton in enclosures].

Controlling the concentrations of silicate, enclosure experiments were conducted in Xinkai Lake to investigate the influence of Si concentration on the growth and succession of phytoplankton communities in a eutrophic freshwater. The results show that with the addition of silicate, the biomass of diatoms increased and the ratio of diatom species to the total significantly increased from 10.2% to 22.

[Variation of nitrogen and phosphorus concentration in water-sediment system and influence of overlying water on the algae growth].

The effect of biosidal treatment of initial sediment, addition of inhibitor and addition of phosphorus on the transform of nitrogen and phosphorus in the sediment-water simulative system were studied. S. quadricaudain was cultured in overlying waters took from the above experiment sets when the above experiment completed.

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands.

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. verticillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD).

[Effects of different concentration ammonium-n on Hydrilla verticillata antioxidant enzymes under Cd stress].

In this paper, submersed plant Hydrilla verticillata was cultivated in a 1/10 Hoagland culture medium added with different concentration NH4 + -N (0, 0. 5, 2. 0, 4.

[Influences of submerged vegetation Hydrilla verticillata on the forms of inorganic and organic phosphorus and potentially exchangeable phosphate in sediments].

The influences of submerged vegetation Hydrilla verticillata on forms of inorganic and organic phosphorous forms and potentially exchangeable phosphate in sediments were investigated under indoors simulating condition. The results show that: (1) Hydrilla verticillata can decrease the amount of OM, CEC and TP evidently ( p < 0.05) and activate the phosphate in sediments.